Hydraulic cushion for sheet-metal presses



April 3, 1928.

F. J. RODE HYDRAULIC CUSHION FOR SHEET-METAL PRESSES Filed. 1'1 21 Patented A r. 3, 1928.

UNITED STAT PATENT OFFICE.

FRIEDRICH J. RODE, OF CHICAGO, ILLINOIS, ASSIGNOR TO MARQUETTE TOOL 80 MFG. COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

HYDRAULIC CUSHION FOR SHEET-METAL PRESSES.

Application filed April 21, 1927. Serial N0. 185,489.

This invention relates to improvements in hydraulic cushions particularly adapted though not necessarily limited in its use forsheet metal presses in which the metal is shaped by means of co-operating dies, one of which dies is reciprocable toward and away from the other, the work beingand piston members, the liquid being circulated from beneath the piston under predetermined conditions to relieve the pressure and then returnto the pressure 'side of the piston for restoring the blank or work holding element. I

A further object is to provide in a cushion of this character improved means for returning the liquid to the pressure side of the piston at a predetermined time in the cycle of operation of the press, and improved means for varying at will the time at which the said liquid is thus returned.

To the attainment of these ends and the accomplishment of other new and useful objects as will appear, the invention consists in the features of novelty in substantially the construction, combination and arrangement of the several parts hereinafter morejfully described and claimed and shown in the accompanying drawing illustrating this invention, and in which The figure is a View partly in side elevation, partly broken away and partly in section of a sheet metal press having an hydraulic cushion constructed in accordance with the principles of this invention applied thereto.

Referring more particularly to the drawing the numeral 10 designates the bed of a press, 11 the uprights, 12 a reciprocating ram or member to which a die 13 is connected, 14 a crank shaft to which-the reciproeating ram 12 is, connected by means of links 15, the shaft being rotated in any suitable manner and from any suitable source of power (not shown). 7

Mounted upon the bed or bolster plate 10 is a die 16, with which the die 13 co operates and encompassing the. die 16 is a blank or work holding element 17 which is supported by means of pins 18 that pass loosely through the bed or bolster plate 10 and engage orrest upon a pressure plate 19.

The pins 18 are of such a length that the upper surface of the blank or work holdlng. element 17 will be normally flush with the upper surface of the die 16 so that the work 20 may rest upon the die and-blank holding member 17.

Allof the above referred to parts are of the ordinary and well known construction.

Supported beneath the bed 10 is a support 21 which is located preferably in a pit 22 and mounted upon the support 21 is a cylinder 23, having a piston 24 reciprocable therein. The piston rod 25 passes through a suitable stuffing box 26 in the top of the cylinder and is connected in any suitable man;

ner such as by means of fastening devices 27,

ing 30 in itswall and the cylinder 29 is providedwith an opening 31, both of which are located preferably at the base of the respective cylinders.

Any suitable connection may be provided between these openings and the connection is provided with a valve casing 32, having a vvalve 33 therein, preferably of the flap type so arranged that it will open to permit liquid to flow from the cylinder 29 into the cylinder 23 under the pressure of the liquid and willrclose under the pressure of the liquid to prevent the liquid from flowing from the cylinder '23 into the cylinder 29.

Leading also from the cylinder 29, preferably through the bottom thereof is an open ing 34 connected with a pipe 35, which in turn is connected with a valve casing 36 in which a valve 37 is arranged, and this valve 37 controls an opening 38 preferably in the bottom of the cylinder 23, the pipe 35 and valve casing 36 forming a communicating 35 piston 24 and through the openin 31, valve chamber 32 and opening 30, there y unseatpassage between the cylinder '23 and cylin der 29.

seat under a predetermined vice- 40.

seate and-the liquid will flow into the pipe and throu h the opening 34 into the cylin-i' abutsa' collar 44 u on the'piston rod 43. Av

The valve37 is controlled by a s ring 39, the stressof which may be varied y'means of an adjusting device 40, such as a screw. The spring 39 holds the valve 37 upon its ressure, which pressure may be varied by adjustin the de- The valve 37- is unseate by the stress or pressure of the liquid in the cylinder 23 beneath the piston 24, and when such pressure overcomes the stress of the spring 39. i

When the ram 12 descends the die 13 will co-operate with the work holder 17 to clamp the work 20. A further movementof the ram 12 in the same direction will lower-the work holder 17, thereby depressing the plate or .pad 19 through the medium of the pins 18. As the pad or plate 19 descends the piston 24 will descend in the cylinder 23 and the liquid in the cylinder 23 beneath the piston will create a resistance pressure to the movementof the piston in such direction until the pressure 'upon the liquid by the piston-24 overcomes the stress of the sprin 39. The valve 37 -will then be under 29 beneat a piston 41 in the cylinder 29. This will cause the piston 41 to rise.

In order to restore the piston 24 and the pad or plate 19 it is necessary to'de ress the iston 41 to force the liquid from t e cyliner 29 back into the cylinder 23 beneath the 'ing the valve 33.

' As a means for thus depressing the cylinder 41 there is provided a resilient element 42 in'the form of a coil spring which encompasses the piston rod 43, one end of the spring abuts the piston 41 and the other end 'lever45 is 'pivota ly mounted intermediate its ends as at 46 to afixed support 47.

One end. of the lever-45 acts upon the spring 42 through the collar 44 and the other end of the lever is prdvidedpreferably with an anti-friction roller 48;. I As the piston 41 rises the spring 42 will also rise causing the collar 44 to slide over the piston rod 43, whichwill rock the lever 45 about its pivot to depress the end carrying the roller 48, thereby allowing the pifs' ton 41 to rise without exerting the spring 42thereupon. I a Means are provid d for storing energy in any stress of the spring 42 to cause'tlie same to become 210- tive at a predetermined time in the cycle of operation of the press so that the liquid will be forced out of the cylinder 29 and into the v ,an hydraulic cushion for resisting the movement of the pad in one direction and emcylinder and piston 7 members one cylinder 23 to restore the piston 24.

Such means'einbodies arod 49 which is here shown as the ram 12. This rod 49 time that the die 13 contacts with the work 20, thereby allowing the piston 41 to rise without exerting .any of the stress of the spring 42 thereon.

When the ram 12starts to ascend the high portion of the cam will engage the roller 48 and rock the 'lever45 in a direction'to store or create energy in the sprin 42 and which ener serves to force the piston 41 downwar ly to eject the liquid from the cylinder e 29 back into the cylinder 23. The stress of the spring 42 under such conditions is preferably just sufiicient to restore the piston 24 by forcing the liquid against the pressure side-thereof.

Obviously by adjusting the cam 51 upon the rod 49 the timein the cycle of operation of the press at which the lever 45 will be '5 rocked to create energy in the spring 42, may

be varied at vwill. s

While the preferred form of the invention has been herein shown and described, it is to be understood that various changes may be made -in the details of construction and in the combination and arrangement of the several parts, within the scope of the claims, without departing from the spirit of this invention.

\What is claimed as new is 1. In a sheet metal press a pressure pad, an hydraulic cushion for resisting the movementtof the pad in one direction and embodying cylinder and piston members one of which 0 erates upon the pad, a second cylinder and piston members, a conduit for leading the liquid from the pressure side of the first said piston to the pressure side of the other piston,,variable resistance means for controlling the conduit and operable .upon by the liquid pressure to open the conduit, a conduit for leading the liquid back from the second to the first, recited cylinder, a check valve in thelast said conduit, and means rendered active by a movable part of the press at a predetermined timein the cycle of operation of the pressfor. moving the piston in the second recited cylinder in a direction to force the liquid therefrom and back into. the first said cylinder to restore the said pressure pad.

2. Ina sheetmetal press. a pressure pad,

some

of which is operable upon the pad, a second cylinder and piston members, a conduit for leading the liquid from one to the other second recited piston, means,- for storing energy in the said resiliently yielding mean;

to cause the second recited piston to force the liquid through the second recited conduit,'and meansconnected with a movable part of the press for thus actuating the second recited means.

3. An hydraulic cushion for sheet metal presses embodying a pair of-cylinder and piston members, two passages forming communications between the cylinders, variable resistance means for controlling one of the passages and adapted to be opened by liquid pressure to permit liquid to flow in one di- -rection therethrough from one cylinder, to 25 the other cylinder, a check valve for controlling-the other passage and adapted to be automatically opened to permit the liquid to flow from one cylinder to the other and in a direction opposite to the first recited direction of flow, a normally inactive resilient element co-operating with one of the pistons and being maintained inactive during the movement of the piston in one direction, a controlling member co-operating with said resilient element, and means operable by a movable part of the press for creating energy in the said resilient element at a predetermined time in the cycle of operation of the pressfor forcing the liquid from the respective cylinder back to the other cylinder.

.4. In a sheet metal working press a pressure pad, an hydraulic cushion for resisting the movement of the pad in one direction and embodying cylinder and piston members, a second cylinder and piston members, a conduit for leading the liquid fromthe pressure side of the first said piston to the pressure side of the second said piston'to move the latter, means for moving the last said piston in the opposite direction to force the liquid back 'to the pressure side of the other piston to restore the latter, variable resistance means for controlling the flow of the liquid from one cylinder to the other in the first recited direction, .the first said means embodying a resilient element movthe moyement ofthe pad in one direction and embodying cylinder and piston mem bers, a second cylinder and piston members, a conduit for leading the liquid from the pressure side of the first said piston to the pressure side of the second said piston to move the latter, means for moving the last said piston in the opposite direction to force the liquid back to the pressure side of the other piston to restore the latter, variable resistance means for controlling the flow ot' the liquid from one cylinder to the other in the first recited direction, the first said means embodying a resilient element movable with therespective piston, a lever mounted upon a fixed pivot, one end of the lever being operable upon said resilient element, and means connected with'a movable part of the press and operable at a predetermined time in the cycle of operation of the press to swing the lever about its pivot to create energy in said resilient element to move the respective pis ton.

6. In a sheet metalworking press a pressure pad, an hydraulic-cushion for resisting the movement of the pad in one direction and embodying cylinder and piston. members, a second cylinder and piston members, a conduit for leading the liquid from the pressure side of the first said piston to the pressure side of the second said piston to move the latter, means for moving the last said piston in the opposite direction to force the liquid back to the pressure side of the other piston to restore the latter, variable resistance means for controlling the flow of the liquid from one cylinder to the other in the first recited direction, the first said means embodying a resilient element movable with the respective piston, a lever mounted upon a fixed pivot, one end of the lever being operable upon said resilient element, and a cam device responsive in its movement to a movable part of the press for swinging the lever about its pivot to create energy in the resilient element to move the respective-piston.

7. In'a sheet metal working press a pressure pad, an hydraulic cushion for resisting the. movement of the pad in one. direction and embodying cylinder and piston members, a second cylinder and piston members,

a conduit for leading the liquid from the pressure side of the first said piston to the pressure side of the. second said piston to move the latter, means for moving the last said piston in the opposite direction toforce the liquid back to the pressure side of the other piston to restore the latter, variable res S sistance means for controlling the flow of the liquid from one cylinder to the other in the first recited direction, the first said means embodying a resilient element movable with the respective piston, a lever mounted upon a fixed pivot, one end of the lever operating upon. the resilient element, and a cam device the respective piston, said lever being movable in the opposite direction independently of the cam and. by the action of the liquid upon the last recited piston.

8. In a sheet metal working press a pressure pad, an hydraulic cushion for resisting the movement of the pad in one direction and embodying cylinder andipiston mem-' bers, a secondcylinder and piston members,

a conduit for leading the liquid from the pressure side of the first said piston to the pressure side of the second said piston to move the latter, means for moving the last said piston'in the oppositedirection to force the'liquid back to the pressure side of the other piston to restore the latter, variable resistance means for controlling the flow of o the liquid from one cylinder to the other in the first recited direction, the first said means embodying a resilient element movable with the respective piston, the first recited means embodying a rod connected with the piston,-

a resilient element carried by the piston and encompassing the rod, a lever mounted upon a fixed pivot, one end of the lever being operable upon the resilient element, and a.

member connected with'a movable-part of the press and adapted to engage and swmg the lever about its pivot ata predetermined time in the cycle of operation of the press to create energy in said resilient element. V

9. In a sheet metal working press a pressure pad, an hydraulic cushion for resisting the movement of the pad in one direc-,

tionand embodying cylinder and piston members, a second cylinder and piston members, a conduit for leading the liquid from' the pressure side of the first said piston to the pressure side of the second said piston to move the latter, means for moving the last said piston in the opposite direction to force the liquid back to the pressure side of the other piston to restore the latter, vari-v able resistance means for controlling the fio'wof the liquid from one cylinder to the other in the first recited direction, the first said means embodying a resilient element recited means embo ying a rod connected with the piston, a resilient element carried by the piston and encompassing the rod, a lever mounted upon a fixed pivot, one end 1 of the lever being operable upon the resilient element, a member connected with a movable part of the press and adapted to engage and swing the lever about its pivot at a predetermined timein the cycle ofoperation of the press to create energy in said resilient element, and means for varying at will the time of operation of the last said member upon the said lever.

mined time in t sure pad, an hydraulic cushion'for reslsting the movement of theiittdin one direction and embodying cylinder and piston members, a resihent' element movable with the piston and normally inactive with respect to the piston, means for forcing the liquid into the c linder to move the piston, a member operable upon the resilient element to create ener y therein to restoretliepiston and thereby orce the liquid frorn'the pressure side of the piston, and means op erable at a predetermined time in the cycle of operation of the press tov actuate the said member.

11. In a sheet metal working press a pressure pad, an hydraulic cushion for resisting the movement of the pad in one direction and embodying cylinder and iston members, a resilient element movable with the piston and normally inactive with respect to the piston, means for forcing theliquid into the cylinder to move the piston, a member operable upon the resilient element to create energy therein to restore the piston and thereby force the liquid from the pressure side of the iston, and means connected with-a movab e part of the press andoperating upon the said member at a predetermined time in the cycle of operation of the press to cause said member to create energy in the resilient member to restore the piston.

12. In a sheet metal working press a pres-- sure pad, an hydraulic cushion for resisting the movement of-the pad in one direction and embodying cylinder and iston members, a resilient element mova le with the piston and normally inactive with respect to' the piston, means for forcing the liquid into the cylinder to move the piston, a member operable upon the resilient element to create energy therein to restore the piston and thereby force the liquid from the pressure side of the piston, a cam device connected with a movable part of the press and operable at a predetermined time in the cycle of operation of the re'ss to create ener in the resilient mem er to restore the plston,

and means for varying at will the time in the operation of the press at which the said cam will operate upon thesaid member.

-13. Ina sheet metalworking press a pressure pad, an hydraulic cushion for resisting the movement of the pad in onefdirectio-n, and embodying cylinder and piston members, a resilient element movable with the. piston and normally inactive with re-. 'spect to the piston, means for forcing liquid into the cylinder to move the piston, a lever pivotally mounted upon a fixedpart of the press, one end of the lever adapted to operate upon said resilient element, and means.

connected with'a movable part of the press and operable uppn the lever at a predetere cycle of operation [of the piston.

14. In a sheet metal working press a pressure pad, an hydraulic cushion for resisting the movement of the ad in one direction and embodying cyldin er and iston members, a resilient e ement mova 1e with the piston and normally inactive with respect to the piston, means for fo reing liquid mto the cyhn'der to move the piston,-a lever pivotally mounted uplon a fixed part of the press, one end of te lever adapted to oper- -ate upon said resilient element, and a cam device adjustably connected with a fixed art of the press and operable upon the said ever to create energy in the resilient element to restore the piston and displace the liqillld from the pressure side of the press.

testimony whereof I have signed my name to this specification, on this 15th day of April, A. D. 1927. w Y Y FREDRICH J. RODE. 

